How's the overall result counted though - is it an equal weighting for speed and distance?

Yes, it's derived by ranking the sum of the distance and speed ranks. You may place whatever significance you like on this value. By this method the top ten ranked are: John Prentice, Euan Adams, Dan Booth, John Darroch, Giles Drake, Ian Taylor, Stuart Prentice, Andrew Taylor, Mark Olsen, and Gabor Dorohazi.